Use pointer-to-pointer idiom to construct linked list

lib/nghttp2_buf.c

@@ -227,8 +227,8 @@ int nghttp2_bufs_wrap_init2(nghttp2_bufs *bufs, uint8_t *const *bufs_in,
                             size_t in_len, size_t buf_len, nghttp2_mem *mem) {
   size_t i = 0;
   nghttp2_buf_chain *cur_chain;
-  nghttp2_buf_chain *pre_chain = NULL;
   nghttp2_buf_chain *head_chain = NULL;
+  nghttp2_buf_chain **dst_chain = &head_chain;
 
   for (i = 0; i < in_len; ++i) {
     uint8_t *begin = bufs_in[i];
@@ -246,13 +246,8 @@ int nghttp2_bufs_wrap_init2(nghttp2_bufs *bufs, uint8_t *const *bufs_in,
     cur_chain->next = NULL;
     nghttp2_buf_wrap_init(&cur_chain->buf, begin, buf_len);
 
-    if (pre_chain) {
-      pre_chain->next = cur_chain;
-    } else {
-      head_chain = cur_chain;
-    }
-
-    pre_chain = cur_chain;
+    *dst_chain = cur_chain;
+    dst_chain = &cur_chain->next;
   }
 
   bufs->mem = mem;